Randomized, double-blind, placebo-controlled trial of oral artemether for the prevention of patent Schistosoma haematobium infections

Artemether is an efficacious antimalarial drug that also displays antischistosomal properties. Laboratory studies have found that artemether curtails the development of adult worms of Schistosoma japonicum, S. mansoni, and S. haematobium, and thus prevents morbidity. These findings have been confirmed in clinical trials for the former two parasites; administered orally once every 2-3 weeks, artemether significantly reduced the incidence and intensity of patent infections. Here, we present the first randomized, double-blind, placebo-controlled trial of artemether against S. haematobium, done in a highly endemic area of Côte d'Ivoire. Urine specimens from 440 schoolchildren were examined over 4 consecutive days, followed by two systematic praziquantel treatments 4 weeks apart. S. haematobium-negative children were randomized to receive 6 mg/kg artemether (N = 161) or placebo (N = 161). Medication was administered orally for a total of six doses once every 4 weeks. Adverse events were assessed 72 hours after medication, and perceived illness episodes were monitored throughout the study period. Incidence and intensity of S. haematobium infections, and microhematuria and macrohematuria were assessed 3 weeks after the final dosing. We also monitored malaria parasitemia and treated positive cases with sulfadoxine-pyrimethamine (SP). Oral artemether was well tolerated. The incidence of patent S. haematobium infections in artemether recipients was significantly lower than in placebo recipients (49% versus 65%, protective efficacy: 0.25, 95% CI: 0.08-0.38, P = 0.007). The geometric mean infection intensity in the artemether group was less than half that of the placebo recipients (3.4 versus 7.4 eggs/10 mL urine, P < 0.001). Heavy S. haematobium infections, microhematuria and macrohematuria, and the incidence of malaria parasitemia were all significantly lower in artemether recipients. In conclusion, previous findings of efficacy of artemether against S. japonicum and S. mansoni were confirmed for S. haematobium, although the protective efficacy was considerably lower. These findings enlarge the scope and potential of artemether and further contribute to discussions of its role as an additional tool for integrated schistosomiasis control.